Excessive noise on analogue outputs

Question

We recently installed 2 PCI6014 boards into a PC running Windows XP. The analogue outputs have about 20mV noise peak-to-peak (I estimate 10mV rms) irrespective of the setting of the output. This seems abnormally large to me, my previous experience was noise was less than 1mV with other boards.

Answer 1

Hello,
If multiple boards are showing the same amount of noise, then it looks to me like you are probably in a noisy environment, or whatever device you are using to measure the noise is not doing a good job.
If you have tried multiple scopes (or your 6014!) and still see the same noise, then there are a couple of things that you can do to remove it.
My first suggestion would not be a new card. After running a quick test in my office, I found that a shielded cable reduced the noise in half. I went from 6 mV noise to 3 mV noise. So this would be my number one suggestion. Here is a list of things that you can change in your system.
1.) Shielded Cable from DAQ Board
2.) Shielded Terminal Block
3.) Shielded Cable from Terminal Block
to Application
4.) Shielded DAQ Board
Lastly, you can check your whole setup with a different computer (put the computer in roughly the same place the current one is). It is possible that you have a �bad� power supply in your current system that is producing lots of noise, in which case you could try buying a new power supply from your local computer store.
Let us know if you have any further questions and good luck with your application!
Best regards,
Justin T.
National Instruments